Differential gear for automobiles.



R. I. FANOHER.

DIFFERENTIAL GEAR FOR AUTOMOBILES.

APPLICATION FILED APR. 20, 1910.

Patented May 28, 1912.

I QB

INVENTOR ATTORNEY.

WITNESSES UNITED STATES FATENT @FFIQE.

ROSMAN I. FANCI-IER, 0F BALDWINSVILLE, NEW YORK, ASSIGNOR OF ONE-HALF TOFRANK L. FULLER, OF SYRACUSE, NEW YORK.

DIFFERENTIAL GEAR FOR AUTOMOBILES.

Specification of Letters Patent.

Patented May 28,1912.

Application filed April 20, 1910. Serial No. 556,581.

To all whom it may concern a Be it known that I, RosMAN I. FANCHER, ofBaldwinsville, in the county of Onondaga, in the State of New York, haveinvented new and useful Improvements in Difierential Gear forAutomobiles, of which the following, taken in connection with theaccompanying drawings, is a full, clear, and exact description.

This invention relates to certain improvements in differential gears forautomobiles to compensate for the differential speeds of the axlesections when the machine is deflected from a straight course as inturning corners.

I am aware that it is common to provide the meeting ends of axlesections with similar beveled gears meshing with one or more interposedpinions or idlers which are revolubly mounted in a suit-able yoke orcasing to which rotary motion is imparted from the main driving shaftthrough the medium of intermeshing gears thereby rotating the axlesections. The number of teeth in mesh between the axle gears andinterposed pinions is comparatively small, usually not exceeding two orthree which take the entire thrust or strain incidental to the operationof the axles and it frequently happens that a sudden increase ordiminution in the speed of one or the other of the wheels, as forexample in passing over an obstruction or depression in the pavement,will cause the stripping or mutilation of such teeth which of coursemakes it necessary to replace the mutilated gear or gears with new ones.Furthermore the gear which is secured to the yoke is necessarily oflarge diameter which requires the use of a gear case considerably largerthan the diameter of the yoke and consequently requires that the chassisor body of the machine be elevated a sufficient distance above it toprevent contact with said gear case under the action of the bodysupporting springs.

The main object is to obviate the use of the usual axle gears andinterposed pinions and consequent breakage, expense and inconvenienceresulting from such use and at the same time to establish a moredurable, positive and efficient connection between the main drivingshaft and axle sections by employing a corparatively short endless chainand suitable sprocket wheels associated in such manner as to establish amore continuous, uniform and greater circumferential contact of thepower transmitting medium around the axle sections than would bepossible with the usual gears. In other words I have sought to provide asimple, compact and economic compensating mechanism which will be moreefficient, more easily responsive and more durable than toothed gearsemployed for the same purpose.

Another object is to assemble the parts in such manner as to permit theuse of a gear case of comparatively small diameter, thereby leaving agreater clearance for the vertical action of the body or chassis thanhas heretofore been practicable.

Another object is to establish comparatively long bearings between thesprocket wheels and adjacent ends of the axle sections to which they arelocked by extending the hubs of the sprocket wheels through a centralaperture in the yoke, thereby forming comparatively long journalbearings between the yoke and sprocket wheels.

Other objects and uses relating to specific parts of the device will bebrought out in the following description.

In the drawings: Figure 1 is a top plan partly in section of my improvedcompensating gearing showing the outer gear case in section and alsoshowing portions of the main driving shaft and axle sections. Fig. 2 isa horizontal sectional view of the same compensating gearing shown inFig. 1, the gear case being omitted. Figs. 3 and 4 are transversesectional views taken respectively on lines 3-3, and 4.-4, Fig. 2, asthe latter would appear in elevation.

In illustrating the operation of my invention, I have shown separatecoaxial axle sections 1 and 1- arranged end to end in the usual mannerand having their ends reduced at 2 and angular or square in crosssection. Mounted upon the inner angular ends of the shaft sections 1 and-1 are separate sprocket wheels -3 having central openings which arealso angular in cross section and closely fitted upon the angularsections 2 to rotate therewith. The hubs of the sprocket wheels areelongated to the full length of the reduced portions 2 with their innerends in close proximity, so as to afford as long bearings therefor aspossible. The face width of the peripheries or chain engaging portionsof the sprocket wheels 3- is considerably less than the length of theirrespective hubs, such face portions being spaced some distance apart forreceiving between them a yoke -thaving a central opening in which theadjacent ends of the hubs of the sprocket wheels are journaled' forindependent rotation with their respective axle sections 1 and -1. Theyoke 4 is provided in one end (preferably the right hand end) with abeveled gear 5- which meshes with a beveled pinion 6 on a main drivingshaft 7, the latter being adapted to be connected to the engine shaft,not necessary to herein illustrate or describe.

Journaled upon the yoke 4t at one side of and at right angles to theaxle sections -1 and -1 is a pair of sprocket wheels -S which in thisinstance are mounted coaxially upon a transverse shaft or spindle 9 inplanes tangential to diametrically opposite sides of the sprocket wheels-3-, the latter being also disposed in planes tangential todiametrically opposite sides of the sprocket wheels -8. In other words,the diameter of the sprocket wheels 8 and distance between the sprocketwheels 3, from center to center, are substantially the same, while thediameter of the sprocket wheels 3 is substantially the same as thedistance from center to center of the sprocket wheels 8.

An endless chain 10 is passed around and engaged with the peripheries ofthe sprocket wheels 3 and --8, opposite sides of the chain beingsubstantially parallel, so that when rotary motion is imparted to oneaxle section in one direction, as in turning corners, opposite rotarymotion will be imparted to the other axle section.

Rotary motion is imparted to the yoke i through the medium of the pinion-6 and gear 5- by which motion the sprocket wheels S are moved bodilyand axially around the axis of the axle sections l and l, the chain -10which laps upon substantially half the circumference of each of thesprocket wheels serving as a means for rotating the sprocket wheels -3and axle sections 1 and 1 connected thereto.

It is apparent that when the machine is driven straight away or in adirect course, the strain upon the chain operating to rotate the axlesections is evenly distributed or equal at all points and owing to thefact that it has a continuous lap or contact throughout at least halfthe circumference of the sprocket wheels 3- the liability of strippingor in any way mutilating the sprockets is reduced to a minimum and atthe same time the chain is quickly responsive to any slight variation ordifference of speed in the two axle sections.

the straining-of the chain owing to the fact that most of its links arein constant engagement with the sprockets of the wheels' The entirecompensating gearing is inclosecl within a suitable gear case 1l havinganti-friction bearings -12 for supporting the axle sections 1 andadditional anti-friction bearings 13- for supporting the inner end ofthe driving shaft 7-. The eccentric weight of the sprocket wheels S- andits supporting shaft -9 is counterbalanced by an opposite counterweight-14 forming apart of the yoke -4t, as best seen in Figs. 2 and 4:.

It will be observed that the radius of the gear 5- is substantiallyequal tothe distance from the axis of the axle section '-1 to theoutside of the sprocket wheels 8 so as to reduce the diameter of thegear as much as possible and thereby permit the use of a comparativelysmall gear case 11--.

The sprocket wheels -8 and portions of V the chain 10 travel in suitableopenings 15 in the adjacent portions of the yoke to permit the action ofthe chain without friction with said yoke.

Another important feature of advantage in the use of this particularform of com pensating gearing is that it obviates the outward end thrustof the axle sections in their bearings produced by the interposition ofpinions between the axle gears of the usual differential gearing therebyrelieving the axle bearings from end thruststrains and at i the sametime increasing the efliciency and longevity of such bearings. Anotherimportant feature of this invention is that it is practically noiselessand reduces the lost motion or back-lash to a minimum.

The operation of my invention will now be readily understood uponreference to'the foregoing description and the accompanying drawings andit is evident that some detail changes may be made without departingfrom the spirit of my invention.

What I claim is:

A differential gear for automobiles comprising coaxial axle sectionsarranged end to end and having their adjacent ends angular in crosssection, separate sprocket wheels mounted on an angular portion of theirrespective shaft sections to rotate there with and having the adjacentends of their ings, a cup-shape yoke having its base pro vided with ahub journaled on said bearings between the sprocket wheels, the open endof the yoke being provided with a bevel gear, a journal bearing on theyoke at right angles to and some distance to one side of the axis of theshaft section midway between the sprocket wheels and at the angle of thebase with the sides of the yoke, an additional pair of sprocket Wheelsmounted on said journal bearing and of substantially the same dianietersas the distance between the centers of the first named sprocket wheels,an endless chain passing around said sprocket Wheels and a driving shafthaving a pinion meshing with the gear.

In witness whereof I have hereunto set my hand on this 16th day of April1910.

' ROSMAN I. FANGHER.

Witnesses:

H. E. CHASE, A. L. QHUMPHREY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

